northrend? aziol nerub empire, lichking with his endless horde of undeads! not enough? how about the secrets of ulduar and 1 of the old gods to help tip the scales? well we also have ronin and the kirintor +the blue and red dragonflight!

ofc pandaria is pretty storng to! the mantid swarm, mogu with their titan tech, the zandalri empire, and the sha!!! along with the quite formidale shandopan!

now lets see... kalimdor have the quiraj empire.. the nightelves.. shitload of old forest thingys from ne lore.. orcs taurens goblins... dranei.. AND ALL THEM FUCKING CENTAURS!
i dont see eastern kingdom having the slightest of chances.

Northrend.
Between Bolvar's endless and almost-self-replicating hordes upon hordes of undead, the Kirin Tor, all the Magnataurs, Walrusmen, Nerubian and titanic inventions, not to mention the Vykrul and all the krakens? Storm giants on the front lines between ranks of Abominations, Magnataurs and Nerubian lords. And don't forget the penguins.

Know what? I think I'm going to go into a lot of detail on this one. Lets consider some of the main aspects of war and see which comes on top.

Major Strongholds: Kalimdor gets this round simply because their cities are easily defensible and have better placement. Consider the fact that they have both coasts covered with at least one major city, and have Thunder Bluff in the middle. Also, each of their cities could be fortified to be impenetrable (Especially Darnassus.) Northrend only has the middle of the continent, leaving it vulnerable to attacks from any direction, and the Eastern Kingdoms only has the west coast covered. Pandaria would likely fall in last place in this round, unless they were allowed to consider the Wandering Isle as theirs. I would then put them in 2nd place.

Forces: I give this one a draw between The Eastern Kingdoms and Kalimdor. Since the cataclysm, both the dwarf and night elf population have been drastically decreased. However, The EK's have the Forsaken (which now has the Val'kyr,) and Kalimdor has the Tauren (who's strength and wisdom isn't given enough credit in WoW.) Northrend is far too weak still from the war against the Lich King, and Pandaria just doesn't have the population to go against any other continents. Also, Kalimdor would have a lot of elementals on their side!

Resources: This one is for sure given to Kalimdor. With the massive forests, wood would never been an issue. The orcs and goblins could produce massive quantities of war machines that could not be matched by the other continents. Also, Kalimdor looks like it would have more farmland to produce food for their armies. The only advantage the other continents may have over Kalimdor in this category is it's access to fresh water, but hell, mages can make that shit anyways.

Leaders: Again, this one would for sure be given to Kalimdor. If the races there put their differences aside and worked together, they would be unstoppable. Malfurion and Tyrande have wisdom and knowledge from living so long, and Velen's unlimited knowledge of the light would work well in their advantage, especially against their undead opponents. The strength of the Orcs and Tauren along with that would be an deadly combination.

Magic: This may be a difficult category. All of the continents have different magics they use in war. Whether it's the arcane, or raising the dead, it is still one of the largest contributors. Personally, I would say that Pandaria wins this because of the Mogu. Their ability to bend flesh could serve them well to create an army. I would rank the Eastern Kingdoms first here, but to raise the dead, you have to kill it first.

Geography: I would give this one to Kalimdor too. Eastern kingdoms would be my obvious choice, simply because of it's large bay areas that could be expended into massive harbours, but the only issue would be having the resources to do it. Kalimdor still has good areas that could be expended on by the water, but also has more habitable mountain ranges (Khaz'Modan is too cold) which could be used to their advantage. Also, if they were pushed back off of the main continent, they could regroup in Darnassus or at the Exodar.

Overall: Kalimdor would be my first choice to win. It's combination of strong forces, superior leaders, and plentiful resources would make it a difficult army to defeat. Eastern Kingdoms comes in 2nd place, with its large number of forces, but badly placed cities and less resources. Northrend and Pandaria would tie for 3rd. They don't have as many strong holds, and are both weaker in forces now.

First off, I have a few basic assumptions for this.
1. Lich King is in the battle as well and does not hold back the Scourge. They are sent to EK split 50/50.
2. Pandaria (Mogu, mantid, sha, pandaren, jinyu, hozen, trolls) attack both EK and Kalimdor.
3. Plan of attack from Northrend would be wiping out EK and Kalimdor top down, then hitting Pandaria.
4. Pandaren forces in Pandaria would wait to attack and just defend their shores from any EK / Kalimdor attackers, with the exception of the Sha, mantid and scouts.
5. Draenei forces will not utilize the Exodar even though it is already functioning again canonically.
6. Any forces in Uldum and AQ would get sent to Pandaria and destroyed by the Shado-Pan, Sha, mogu and mantid.
7. The only murloc / naga forces would be the ones specifically on the shores of a continent. So EK gets naga from Vashj'ir.
8. Fire destroys Scourge and makes it impossible to reanimate them.
9. The Sha are helping fight for Pandaria cause no Pandaria means no Sha. Sha can only be defeated, not killed.
10. Sha are highly mobile.

KALIMDOR
Any and all forces from Uldum, AQ, Tanaris, and surrounding areas immediately group up to attack the shores of Pandaria. However, Pandaria is not yet playing offense and is waiting for the waves of armies sent to them. These Southern EK armies are decimated by the combined forces of the mantid, sha, pandaren, etc. The Night Elves and worgen would be wiped out from Teldrassil because the Scourge would burn the whole tree down and kill any and all who attempt to escape. That takes away a sizable portion of their army and adds it to the undead onslaught. Draenei could go a few ways: fuck this we're leaving and they take off on the Exodar, or they stand their ground to defend against the scourge, or they go to the main continent and help the night elves. If we say they stay and split between defense and going to the main continent, either way, they're no better off than the night elves. The Scourge go to the Azuremyst / Bloodmyst Isles and decimate the Draenish forces. Nerubian forces scatter down to Winterspring with Taunka on their backs, assaulting the Night Elf and Goblin peoples there. The Taunka prove not to be difficult foes and most fall in battle. The Winterspring forces fail to hold back the Nerubians and they destroy the furbolgs and make their way to Moonglade.
The Scourge moves to Ashenvale and destroy the naga and Shatterspear trolls while making their way to Moonglade, where Nerubian forces are succeeding in destroying the Cenarion Circle. The Scourge army has doubled in size and makes their way through Kalimdor zones one by one, picking off eveyone they can. The goblins of Azshara have been using the cannon in Bilgewater Harbor to attack Stormwind, Ironforge, and Tol Barad from afar, though not without hitting other cities of the continent as well. The Scourge splits 70/30, unbeknownst to the mortal forces, with the most going to Ashenvale. Night Elves and orcs try to fight them back to no avail. Orgrimmar sends aid in the form of Tauren, Goblins, and trolls. Some smart Goblin decides that burning the forest would destroy a large portion of the Scourge, so the Night Elf and Tauren druids help the Goblins rain fire through the forest, successfully destroying large portions of the Scourge. The other part of the Scourge, however, has gone to Azshara and attacked unsuspecting Goblins and Night Elves. They join the Scourge army as it goes through an unsuspecting Orgrimmar into Ashenvale.
While this has been occurring, the Shas of Fear and Doubt have grown due to the fear and doubt the Pandarian forces have due to the war, afraid they may be hit with strong armies and destroyed. The Mantid decide to go on the offensive and go to Southern Kalimdor, easily destroying everything in their path. This angers many other races of Pandaria, who were afraid that going on the offense would mean the continent's downfall. The Sha of Anger grows as well.
Since the peoples of central / south central Kalimdor are not suspecting attacks from the Scourge for at least a week, they prepare, but they still rest up for their strength. The Mantid clear out all zones south of Mulgore, with the exception of the northern part of South Barrens. They opt to ignore Thunder Bluff at first, focusing attacks on different settlements in Mulgore. The Tauren do not realize this strategy till it's too late and, with their forces worn thin, Thunder Bluff is attacked and falls. The Mantid go through to Desolace, only to find it deserted as its residents have fled.
The Scourge, although heavily thinned and cleared of any Nerubian forces, goes through Durotar while the Mantid clear out Stonetalon. They make their way east as the Scourge makes its way west and meet at the Crossroads. The Mantid forces and Scourge forces battle it out at the Crossroads, along with the orcish population. The Horde peoples of Crossroads meet their fate quickly. Both sides get attacks from....the Night Elves? The people of Desolace had fled to the Overgrowth, hoping to use it to their advantage in a last ditch effort to defeat the Mantid and Scourge. The Mantid, smarter than the Scourge, realize that the Night Elves are using the Overgrowth to pull Scourge into the lava that separates the two halves of the Barrens. They agree to a quick truce, knowing that a world run by Scourge would never again see life. Together they defeat the Scourge armies, the bodies burning in the lava. The mantid and Night Elves agree to go up to Northrend in hopes of defeating the Lich King.

---------- Post added 2013-02-06 at 04:00 PM ----------

EASTERN KINGDOMS
Much of Eastern Kingdoms is attacked before they can even react. Before it is destroyed, the Goblins of Bilgewater Harbor had used the cannon there to attack many EK lands. Undercity caves in due to the bombing of Lordaeron. The mountains of Dun Morogh are bombed as well, caving in Gnomeregan and Ironforge. Stormwind is attacked to make the whole city match the Park. Blackrock Mountain becomes Blackrock Mound. Gilneas and Tol Barad are sunken. The Scourge eats through the Blood Elves like they did the High Elves. The trolls in Ghostlands don't stand a chance. The elves and trolls bulked up the Scourge forces. Remaining Scourge in Lordaeron join their brethren. They make their way through Lordaeron, adding to their numbers as they do. The Lich King trails behind, raising himself new armies. The worgen and Forsaken put up a good fight, and even seem to have an upper hand when they're in Southshore, but are eventually pushed down into Dun Modr, where Dwarven/Gnomish defenses are in place, along with Blackrock orc armies.
Everywhere south of the Burning Steppes has gone to Pandaria in large forces by zone. Wave by wave, they are picked off slowly by the strong sha defenses. The Shas of Anger, Fear, and Doubt are in the Jade Forest, awaiting the attackers and easily destroying them. The violence gives power to the Sha of Violence, who aids the other Sha in defending the Jade Forest. Some of the Goblins / humans / trolls attacking Pandaria are overcome by the Sha and fight their own brethren. During this time, the Pandaren send scouts to EK to see who remains. They find small, temporary settlements and set them aflame. The Pandaren scouts come across Booty Bay and assassinate military leaders before attempting to set the city aflame. They are caught and killed, not before taking out quite a few Goblins with them. However, the loss of military leaders hurts the forces going to Pandaria, who lose a lot of their organisation. In the end, the Sha forces win against the attacks.
The Scourge fight at Dun Modr at an almost stand still, where the Scourge will drop only to be risen once more. The gnomes try bombing them, while the worgen attempt to pick them off individually, the dwarves shoot at them, and the Forsaken group up in an attempt to figure out what they should strategically do. Naga forces from Vashj'ir are on their way, but are also attempting to attack Pandaria, though not to much success.
The Lich King, with a small, elite band of Scourge, heads to Raventusk Village overnight as the rest of the Scourge battle with mortals at Dun Modr. They kill the trolls in their sleep and add them to their numbers. Since the Scourge had skipped the Hinterlands and many dwarves from their were killed assisting Refuge Point, the Lich King and his band of dead go through the zone, adding the dead to their force and killing any living. He makes his way through the mountains, killing the Hill Dwarves there, so that he may go behind the forces at Dun Modr and destroy them.
The Gnomes bomb the bridge at Dun Modr, leaving the Scourge to fall below. This leaves it a battle between casters and rangers....at least, until the Scourge cross over. This about the time news of the Mantid and Night Elves pact has reached Pandaria from a Mantid scout. The Mogu, Pandaren, Jinyu, Hozen, trolls, Sha and Yaungol make a plan for offensive action. The Sha will continue to defend the shores of the continent, while a large band of Jinyu, Hozen, Yaungol and Mogu will make their way to the shores of Booty Bay. A large contingent of trolls will sail up to the shores of Westfall. These bands from Pandaria clear out any remaining forces they find and meet up in Duskwood. Together they slowly clear out anything remaining in Azeroth.

---------- Post added 2013-02-06 at 04:21 PM ----------

NORTHREND
The Mantid and Night Elves, while supposed to be teamed up, turn on each other. The Mantid decimate the Night Elves. The Mantid, on their way north to a land they've never been, come across the cannon in Bilgewater Harbor. They find instructions on how to use it and quickly put it to use. They bomb what they can of Northrend (which ain't much). Most leave to return to Pandaria. A few stay in the Harbor, bombing the EK.

THE LAST BATTLE
The Pandarian forces make their way to Khaz Modan only to find it cleared out. The Dwarves have all been sent to Dun Modr to fight the Scourge. The Lich King has increased his armies by destroying Naga as they come to the shores of Menethil Harbor. The enlarged force hits the rest of the Dwarven lands while the main Scourge force takes the upper hand in Dun Modr. The Pandaria force moves from Azeroth to the shores of the Twilight Highlands. They are met by the Lich King's growing elite force and, while taking down a few of his force, are eventually destroyed. The Scourge finally overruns Dun Modr and makes their way down to Pandaria.
The Mantid at Bilgewater Harbor await messages from home.
The Sha attack the Scourge as it comes, but can only do so well. The Lich King forces eat through to the central area of the Jade Forest. A crazy Hozen, in an attempt to gain the upper hand, sets fire to the forest. The Pandarian forces retreat to the Valley of Four Winds and set fire to much of the forest as they do. Much of the Scourge burns.
When the Mantid return from Kalimdor, they find that the Lich King and his forces, while severly dwindled, have chased the Pandarian forces through the Veiled Stair into the mountains. They send a scout to Bilgewater Harbor, hoping the message will get their soon enough, so that they can bomb the mountain while the Lich King and his forces are on it. The Yaungol set fire to what they can, grabbing the Scourge one by one and burning their bodies. They eventually retreat. The Sha weaken the forces, but are weakened themselves. The Mantid pick off Scourge, and the Pandaren attempt to gain an upper hand. The Lich King is nowhere to be found.
The Horde and Alliance forces of Pandaria attack the Scourge from behind and eventually the forces dwindle enough that they Pandarian armies believe they will win. This brings the Lich King out, who had been in the Temple of White Tiger, Peak of Serenity, and Shado-Pan Monastery, killing and raising forces. He fights a large mix of Mogu, trolls and Pandaren up the mountain when the Mantid in Bilgewater Harbor gets the message. Aiming for Mount Neverest, he shoots off the cannon randomly, destroying the mountain. The mount falls, killing the Lich King and the large band of Mogu, troll, and Pandaren.
Pandaria has won.

---------- Post added 2013-02-06 at 04:24 PM ----------

tl;dr
Northrend attacks Kalimdor and EK, Pandaria stays on the defense, Scourge wipe out most of both continents, Pandaria sends forces to kill southern half of both continents, the cannon of Bilgewater Harbor is OP, Lich King dies on Mount Neverest.

I am an altoholic, but never got toons past 30. I am trying to refine my ways.

Kalimdor. Ancients, Dragons, a majority of the Horde's muscle, if the Night Elves were aligned with the Orcs they wouldn't be written as the total crap they are written as now, then you have the Draenei, Tol'vir, Silithids, Qiraji to counter the Mantid, Nordrassil, Tauren blah blah blah.
The scourge would be returned to the dirt where they belong by the might of Nature and Kalimdor would have Ancients, Elune, the strongest Light Wielders, most powerful Shaman, Druids, Hunters and Warriors to come down.

Kalimdor. Ancients, Dragons, a majority of the Horde's muscle, if the Night Elves were aligned with the Orcs they wouldn't be written as the total crap they are written as now, then you have the Draenei, Tol'vir, Silithids, Qiraji to counter the Mantid, Nordrassil, Tauren blah blah blah.
The scourge would be returned to the dirt where they belong by the might of Nature.

Look its Constellation in another thread hating on the orcs again. Who could have seen it. Don't be mad we won and burned ashenvale to the ground. We needed the lumber.

I'd have to go with pandaria.
While northrend has an "endless" army, it are mainly braindead zombies incapable of giving a proper fight.

It shouldn't be a problem for the zandalari and the mogu to simply walk over the hordes of undeath, laying siege to icecrown citadel and kicking the lich king his ass.
Not to mention, the scourge can't raise bodies that are out of their reach, as long as the pandarian forces keep the dead bodies behind their lines, the scourge has very little to raise.

I have a question, since Ebon Hold is in EK does that mean EK would have every DK?

There's plenty of Ebon Blade death knights (maybe even more) in Northrend. Only the ziggurat Ebon Hold contains death knights in EK, which aren't that many. Also, Icecrown Citadel and Naxxramas houses legions of death knights aswell :P